The present invention relates to a method for sequential programming of an injection molding cycle of an injection molding machine.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
An injection molding cycle, i.e., the operation of an injection molding machine, can be programmed in a conventional manner with a stored program controller (SPS) located at the injection molding machine itself (online) or at a separate terminal located remote from the injection molding machine (off-line). When programmed online, the injection molding machine is unavailable for production during a considerable length of time. Conversely, when programmed off-line, the injection molding machine typically needs to be stopped only briefly to make fine adjustments in the programming.
These stored program controllers typically include data processing programs for setup and operation of an injection molding machine. Different manufacturers of injection molding machines typically offer a stored program control customized for their own (proprietary) machine program. Disadvantageously, the process flow of an injection molding cycle in these controllers cannot be changed or only with the assistance from the machine manufacturer. The user or custom molder is prevented from programming the controller.
Stored program process controllers are now available with tools which enable the user or custom molder to assemble the process flow of an injection molding cycle from predefined elements (macros). Such stored program process controllers are described in the publication “Kunststoffe” (Plastics), Vol. 08/2003, pages 46-49.
A custom molder, who operates injection molding machines from different manufacturers, should have experience with different stored program process controllers so as to be able to correctly program all process flows and movements required for fabricating a certain product.
It already proves difficult to be competent with a stored program process control from a single manufacturer; and if a person is not constantly involved with this particular program and/or if a new process needs to be programmed after some time (for example, because a different product needs to be manufactured), then the person must become again familiar with this program, which may be quite time-consuming. The situation becomes more complicated, when injection molding machines from different manufacturers must be programmed which requires familiarity with different stored program process controllers.
Process flow diagrams from mold manufacturers provide some support for programming a process flow of an injection molding machine. Such flow diagrams describe and illustrate in detail the required movement and timing of the parts of a mold, so that the molded part is produced correctly and can be easily removed from the mold. However, these flow diagrams must still be entered into the stored program controller (SPS) or converted to the “correct” process programming sequence, which requires a certain familiarity with these controllers. Moreover, these flow diagrams are not available for each mold. In addition, errors may occur when a data describing positions, such as “advanced” and “returned”, or “moved in” and “moved out” are not unambiguous. Moreover, operating personnel frequently does not have the required technical knowledge of the injection molding machines and molds.
All stored program controllers (SPS) and the afore-described stored program process controllers have an inherent problem in that the entire injection molding cycle is first entered in the controller and thereafter executed in its entirety, without being able to risk-free test the cycle or sections of the cycle. Any errors can severely damage the molds.
Programming of machines can be simplified with so-called “teach-in systems” which represent additional tools designed to facilitate programming of complex machines and which typically do not require programming experience or familiarity with the machine control. DE 199 00 117 A1 discloses a teach-in system for programming grinding machines or other machine tools. This teach-in system includes a graphic user interface for the display of blanks, workpieces and tools. The illustrated elements can be placed in any relation with one another by moving corresponding control elements. The resulting movements are recorded by the teach-in module and translated into a machine control program; alternatively, an existing machine control program is altered by these movements. This system represents a so-called virtual teach-in system.
Other teach-in methods and teach-in systems are known from programmable industrial robots, for example, for teaching the controller of a robot the movement of a manipulator arm relative to a workpiece (teaching the robot). The desired movement of the robot is manually entered into an input device, either numerically or graphically. A data processing program converts the corresponding input values into a “movement program” for the industrial robot, i.e., the movement is programmed automatically. Teach-in systems for industrial robots are disclosed, for example, in EP 0 792 726 B1 and U.S. Pat. No. 4,224,501.
It would therefore be desirable and advantageous to provide an improved method for simplifying programming the process flow of an injection molding cycle of an injection molding machine, which obviates prior art shortcomings and which can be used independent of manufacturer-specific programs and hence universally with any injection molding machine.